ANA CONTINUES TO PRODUCE PULSING CENTRAL DEEP CONVECTION. RECENTIMAGES HAVE ALSO SHOWN TRANSIENT WARM SPOTS APPEARING IN THEINFRARED IMAGERY. AN SSMIS PASS FROM 1912 UTC INDICATED ANEYEWALL-LIKE STRUCTURE TO THE EAST OF THE CENTER. EARLIER MICROWAVEPASSES FROM 1812 AND 1557 UTC SHOWED THIS FEATURE TO BE A LITTLEBETTER DEFINED. DVORAK INTENSITY ESTIMATES FROM THE FIX AGENCIESCAME IN AT 45 KT/35 KT/30 KT FROM PHFO/SAB/JTWC. CIMSS SATCON WAS 49KT WITH THE AMSU COMPONENT INDICATING 58 KT. GIVEN THE MICROWAVESTRUCTURE FROM THE MOST RECENT PASSES AND THE OCCASIONAL WARMSPOTS...THE INITIAL INTENSITY WILL LEAN TOWARD THE SATCON AND AMSUESTIMATES AND HAS BEEN INCREASED TO 55 KT FOR THIS FORECAST CYCLE.

THE INTIAL MOTION IS 020/11 KT AS ANA MOVES BETWEEN AMID-LEVEL RIDGE TO ITS SOUTHEAST AND AN APPROACHING LOW PRESSURESYSTEM TO THE NORTHWEST. THIS IS A FASTER MOVEMENT FROM THEPREVIOUS ADVISORY PACKAGE AND SIGNALS THE START OF AN EXPECTEDACCELERATION TOWARD THE NORTHEAST. OBJECTIVE AIDS ARE RATHERTIGHTLY PACKED...EVEN BEYOND DAY 3 WHEN ANA TRANSITIONS TO ANEXTRATROPICAL SYSTEM. THUS...THE FORECAST TRACK CLOSELY FOLLOWS THEPREVIOUS PACKAGE THROUGH 36 HOURS EXCEPT FOR A SLIGHT NORTHWARDNUDGE TO ALIGN IT CLOSER TO THE DYNAMIC CONSENSUS. BEYOND 36HOURS...THE FORECAST TRACK IS BASED ON THE GLOBAL MODELS ANDGUIDANCE FROM THE NOAA OCEAN PREDICTION CENTER AS ANA HEADS TOWARDTHE NORTH AMERICAN CONTINENT.

IN THE SHORT TERM...ANA WILL BE UNDER MODEST VERTICAL WIND SHEARAND IS TRANSITING MARGINAL SEA SURFACE TEMPERATURECONDITIONS. THIS IS EXPECTED TO ALLOW A MAINTENANCE OF STRONGTROPICAL STORM INTENSITIES...WHICH IS CONSISTENT WITH THE SHIPSGUIDANCE THROUGH 36 HOURS. BEYOND 36 HOURS...ANA SHOULD BEGIN ANEXTRATROPICAL TRANSITION ALONG A TRACK THAT WILL TAKE IT OVERPROGRESSIVELY COOLER TEMPERATURES AND INCREASING VERTICAL SHEAR.THUS...THE INTENSITY FORECAST BEYOND 36 HOURS IS LARGELY BASED ONNOAA OCEAN PREDICTION CENTER GUIDANCE WHICH CALLS FOR SLOWWEAKENING AS AN EXTRATROPICAL CYCLONE UNTIL DISSIPATION AT 120HOURS.

The posts in this forum are NOT official forecasts and should not be used as such. Posts are NOT endorsed by any professional institution or STORM2K.org. For official information and forecasts, please refer to NHC and NWS products.

The posts in this forum are NOT official forecasts and should not be used as such. Posts are NOT endorsed by any professional institution or STORM2K.org. For official information and forecasts, please refer to NHC and NWS products.

THE STRUCTURE OF ANA HAS IMPROVED TODAY WITH THE DEVELOPMENT OF ANEYE AROUND 2200 UTC. THIS MAY BE ANA/S BEST EYE THROUGH ITS LIFECYCLE THUS FAR. EYEWALL CLOUD TOP TEMPERATURES HAVE WARMED THROUGHTHE AFTERNOON BUT THE EYE HAS REMAINED INTACT. DVORAK FIXES CAME INWITH 65 KT FROM PHFO...SAB AND JTWC...WITH CONSTRAINTS BROKEN BY ALLTHREE. GIVEN THIS EYE DEVELOPMENT...AND THAT IT HAS NOT BEEN AONE-IMAGE TRANSIENT FEATURE...THE INITIAL INTENSITY HAS BEENINCREASED TO 65 KT.

ANA IS ACCELERATING TOWARD THE NORTHEAST...MOVING AT 040/20 KTBETWEEN A MID-LEVEL HIGH TO THE SOUTHEAST AND AN APPROACHING LOWPRESSURE SYSTEM TO THE NORTHWEST. THE MODEL GUIDANCE IS TIGHTLYGROUPED THROUGH THE CYCLE WITH ONLY SMALL CHANGES IN POSITIONS.THUS...THE FORECAST TRACK FOR THIS PACKAGE IS CLOSE TO THE PREVIOUSPACKAGE WITH THE 48 THROUGH 96 HOUR POINTS BASED ON GUIDANCE FROMTHE NOAA OCEAN PREDICTION CENTER WHICH USED A BLEND OF THE UKMET...GFS AND ECMWF GLOBAL MODELS.

WHILE VERTICAL SHEAR IS CURRENTLY WEAK NEAR ANA...THE SEA SURFACETEMPERATURES ARE RAPIDLY DECREASING ALONG ITS FORECAST TRACK.THEREFORE...THE FORECAST DOES NOT CALL FOR ADDITIONALINTENSIFICATION BUT HOLDS ANA AT A MINIMAL HURRICANE LEVEL OF 65 KTFOR 12 HOURS FOLLOWED BY A WEAKENING TREND. THIS IS CONSISTENT WITHSHIPS GUIDANCE THROUGH 36 HOURS DURING WHICH TIME ANA IS EXPECTED TOTRANSITION TO EXTRATROPICAL STATUS. BEYOND 36 HOURS...THE INTENSITYFORECAST IS BASED ON GUIDANCE FROM THE NOAA OCEAN PREDICTION CENTER.

Of those 8, how many actually intensified to hurricane status above 30N? We're having a discussion about this in the EPAC FB group right now.

I don't use FB. Off the top of my head, I can think of the 75 Pacific Northwest and Julio 14.

Julio missed by less than a degree (29.4N). The '75 system is pretty wild....sort of the Pacific's version of "The Perfect Storm" - instead of Hurricane Grace it was Ilsa that was ingested and formed a new hurricane.

Trying to find some track info about a system from 1957 that may be another one.

Well, of course it is. It's in the BT database as such and that's what we have to go on. One other thing to consider is that 1957 fits the pattern in that it was a moderate warm ENSO phase, which would lend itself to enhanced CPAC TC activity, and the potential for higher latitude intensification.

THE EYE OF HURRICANE ANA REMAINS WELL DEFINED IN INFRARED SATELLITEIMAGERY THIS EVENING. AS A RESULT...ALL OF SUBJECTIVE DVORAKESTIMATES OF CURRENT INTENSITY FROM PHFO...SAB AND JTWC WERE 4.0/65KT. THE MOST RECENT ENVIRONMENTAL VERTICAL WIND SHEAR ESTIMATES FORANA FROM UW-CIMSS AND SHIPS ARE 5 TO 10 KT FROM THE NORTHWEST.

ANA CONTINUES MOVING RAPIDLY NORTHEASTWARD...045/21 KT THIS EVENING.THIS FORWARD MOTION IS DUE TO THE DEEP STEERING FLOW BETWEEN AMIDDLE- TROPOSPHERE ANTICYCLONE TO THE SOUTHEAST...AND A MIDDLE- TOUPPER-LEVEL TROUGH DIGGING DOWN TO THE NORTHWEST OF ANA. THE LATESTMODEL GUIDANCE REMAINS TIGHTLY CLUSTERED THROUGH THIS WEEKEND.THEREFORE...THE MODEL CONSENSUS...OR TVCN...CONTINUES TO BE THEPREFERRED TRACK. AS A RESULT...THE LATEST TRACK FORECAST THROUGH 36 HOURS HAS ONLY SUBTLE CHANGES FROM THE PREVIOUS ADVISORY. NOTE THAT THE 36 TO 96 HOUR FORECAST POSITIONS WERE SUPPLIED BY THE NOAA OCEAN PREDICTION CENTER...OR OPC.

IN REGARDS TO THE FORECAST INTENSITY...THE VERTICAL WIND SHEAR ISEXPECTED TO BE RELATIVELY LOW THROUGH SATURDAY. HOWEVER...ANA ISMOVING OVER INCREASINGLY COOLER SEA SURFACE TEMPERATURES ALONG ITSFORECAST TRACK. THESE DETRIMENTAL CONDITIONS SHOULD BEGIN TO TAKE ATOLL ON THE MAINTENANCE OF THE DEEP CONVECTION NEAR THE CORE OF THEHURRICANE LATER TONIGHT OR SATURDAY. THE CONSENSUS INTENSITYGUIDANCE...OR ICON...SHOWS THIS WEAKENING TREND. WE ARE FORECASTINGANA TO WEAKEN TO A STRONG TROPICAL STORM WITHIN THE NEXT 12 HOURS.SOME ADDITIONAL WEAKENING IS EXPECTED SATURDAY NIGHT. BASED ON THELATEST INPUT FROM OPC...ANA IS EXPECTED TO TRANSITION TO A STRONGEXTRATROPICAL LOW...LIKELY WITH STORM FORCE WINDS...WITHIN 36 HOURS.THEREFORE...THE INTENSITY FORECAST AND WIND RADII STARTING SUNDAYMORNING ARE BASED ON THE LATEST GUIDANCE FROM OPC.